Electrospinning needle

Abstract

The utility model discloses a kind of electrospinning needle heads, belong to electrospinning technical field.The needle head includes needle holder, inner needle head, outer capillary and connecting limiting mechanism, outer capillary sliding sleeve is set on inner needle head tail end outside, and axial relative movement and automatic reset are realized by elastic connecting limiting mechanism.When needle head is blocked, exert external force to make outer capillary axial movement relative to inner needle head, utilize mechanical shearing action to remove inner wall residue, and automatically reset after releasing external force.The utility model realizes not to stop machine quick cleaning, solves the problem that traditional needle head needs to be disassembled and replaced or manually dredged after being blocked, significantly reduces labor intensity and maintenance cost.Adopt split type differentiation material design, outer capillary uses high-grade corrosion-resistant material, inner needle head and needle holder use ordinary conductive material.It is suitable for the continuous production of multi-needle array electrospinning system.

Description

Technical Field

[0001] This utility model belongs to the field of electrospinning technology and relates to an electrospinning needle. Background Technology

[0002] Nanofibers are ultrafine fibers with diameters ranging from 1 to 1000 nanometers. They possess characteristics such as high specific surface area, high porosity, excellent mechanical properties, and good surface activity, showing broad application prospects in fields such as air filtration, water treatment, biomedical materials, sensors, and energy storage and conversion. Electrospinning technology is currently one of the most important and effective methods for preparing nanofibers. Its principle is to use a high-voltage electrostatic field to overcome the surface tension of polymer solutions or melts, forming a Taylor cone between the spinneret and the receiving device, thereby generating a high-speed jet. After solvent evaporation or cooling and solidification, the nanofiber is deposited on the receiver to form a nanofiber nonwoven fabric.

[0003] With the increasing demand for nanofiber industrialization, multi-needle array electrospinning technology has become an important means to increase production. However, in actual production, needle clogging severely restricts the industrial application of electrospinning technology. The main causes of clogging include: solvent evaporation in the spinning solution leading to solute precipitation on the inner wall of the needle, polymer gelation, entry of micro-dust particles from the environment, and accumulation of electrochemical reaction products induced by the high-voltage electrostatic field. Once clogging occurs, it not only prevents the corresponding needle from producing fibers, resulting in uneven fiber film thickness and pores, but the clogging material may also flow with the spinning solution and contaminate other needles, affecting the quality of the entire batch of products.

[0004] To address the problem of needle clogging, existing technologies mainly employ the following solutions: First, periodic shutdowns for manual unclogging, where operators use fine needles or wires to physically unclog the needle. This method is labor-intensive, inefficient, and prone to damaging the inner wall of the needle. Second, ultrasonic cleaning or chemical solvent soaking is used, requiring the needle to be removed from the equipment, which is time-consuming, and frequent disassembly and reassembly affect the equipment's accuracy. Third, replaceable needles are designed, allowing for direct replacement after clogging, but this is costly, and the replacement process also requires machine shutdown. Fourth, anti-clogging needle structures are developed, such as heating the needle to accelerate solvent evaporation or adding a solvent flushing system, but these are complex, increasing equipment costs and energy consumption.

[0005] Therefore, there is an urgent need to develop an electrospinning needle that is simple in structure, easy to operate, low in cost, and capable of rapid in-situ cleaning, in order to solve the above-mentioned technical problems and promote the industrialization of electrospinning technology. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an electrospinning needle. This needle adopts a split, relatively movable structure, which can quickly remove blockages without disassembly, significantly shortening downtime and reducing maintenance costs. To achieve the above objectives, the technical solution adopted by this invention is as follows.

[0007] An electrospinning needle, comprising: Needle holder, connected to the spinning solution supply system; The inner needle is fixedly mounted on the needle seat and has a spinning liquid flow channel that extends along the axial direction. The outer capillary is slidably sleeved on the outer side of the end of the inner needle. The inner wall of the outer capillary and the outer wall of the inner needle form a sliding tight fit, and the two can move relative to each other along the axial direction. A connecting limiting mechanism is disposed between the inner needle and the outer capillary to keep the outer capillary and the inner needle coaxially connected; the connecting limiting mechanism is configured to allow the outer capillary to move axially relative to the inner needle under the action of external force, and to automatically return the outer capillary to the initial working position after the external force is removed. The tip of the outer capillary extends beyond the tip of the inner needle, forming an annular gap for spinning.

[0008] This utility model provides an electrostatic spinning needle that, through a combination of sliding fit and elastic reset mechanism, achieves in-situ cleaning when the needle is clogged, eliminating the need for disassembly and replacement, significantly shortening downtime and improving production efficiency; at the same time, it maintains structural stability during the spinning process, ensuring consistent fiber quality.

[0009] Furthermore, the connection and limiting mechanism is an elastic sleeve, with its two ends respectively fitted onto the outer walls of the inner needle and the outer capillary. Connection and limiting are achieved through radial contraction force. Using an elastic sleeve as the connection and limiting mechanism results in a simple structure, low cost, and reliable connection and automatic reset functions without the need for additional fasteners, facilitating rapid on-site operation.

[0010] Furthermore, the sleeve is made of rubber or silicone.

[0011] Furthermore, the connection limiting mechanism is connected to the inner needle and the outer capillary via a socket connection. The outer walls of the inner needle and the outer capillary are provided with annular grooves, and the two ends of the connection limiting mechanism are embedded in the annular grooves to form axial limiting.

[0012] Furthermore, the surface roughness Ra of the inner wall of the outer capillary is ≤0.4μm, and the surface roughness Ra of the outer wall of the inner needle is ≤0.8μm, with a fitting gap of 0.01-0.05mm. By precisely controlling the surface roughness and fitting gap, it is ensured that the spinning solution does not leak under high pressure, while also ensuring smooth axial sliding, reducing frictional resistance during cleaning, and preventing jamming.

[0013] Furthermore, the inner needle has a length of 13-50 mm and an outer diameter of 0.5-2 mm; the outer capillary has a length of 13-16 mm, an inner diameter of 0.6-2.1 mm, and a wall thickness of 0.1-0.3 mm. This limited size range accommodates spinning solutions of varying viscosities. The inner needle's length being greater than the outer capillary ensures that the tip of the inner needle can completely scrape away residue from the inner wall of the outer capillary during cleaning, thus optimizing the cleaning effect.

[0014] Furthermore, the tip of the outer capillary extends 3-5 mm beyond the tip of the inner needle, forming a stable Taylor cone formation region. By limiting the tip protrusion distance, a stable Taylor cone is formed during spinning, optimizing the electric field distribution, avoiding electric field distortion and jet instability caused by the exposed inner needle, and ensuring fiber diameter uniformity.

[0015] Furthermore, the outer wall of the inner needle tip is provided with a guide cone surface, and the inlet end of the outer capillary is provided with a corresponding guide chamfer. The cone angle of the guide cone surface is 15°-30°. The guide cone surface design facilitates the quick installation of the outer capillary and also plays a centering role during the cleaning process, preventing radial displacement of the outer capillary during axial movement and avoiding damage to the mating surfaces.

[0016] Furthermore, the outer wall of the outer capillary is provided with anti-slip texture or operating flange. The anti-slip texture is knurled, textured, or has axial ribs, and the operating flange is an annular boss or symmetrically arranged lugs. This increases operational convenience, allowing operators to effectively apply force for axial movement even when wearing gloves, thus improving the safety and efficiency of cleaning operations.

[0017] Compared with the prior art, the present invention has the following significant advantages: In-situ rapid cleaning improves production efficiency: The sliding fit and elastic reset mechanism enable in-situ cleaning when the needle is blocked, without the need to disassemble or replace the needle or stop the machine for soaking and cleaning. The cleaning operation can be completed within 1-2 minutes, significantly shortening downtime and improving equipment utilization and production efficiency.

[0018] Thorough cleaning reduces recurrence rate: Mechanical shearing action thoroughly removes residue from the inner wall, and vacuum suction or reverse air blowing can completely remove loose material, preventing residue from circulating in the system and reducing the recurrence rate of blockage by more than 60%.

[0019] The split design allows for the use of different materials to reduce costs: based on corrosion mechanism analysis, only the outer capillary uses high-grade corrosion-resistant materials, while the inner needle and needle seat use ordinary conductive materials. This reduces material costs by 30%-50% while ensuring the corrosion resistance of key parts. Furthermore, the inner needle is reusable, and only the outer capillary needs to be replaced periodically, further reducing operating costs.

[0020] Simple structure and easy operation: The flexible sleeve connection method requires no additional fasteners and complex mechanisms, has a compact structure, is lightweight, and is easy to apply in multi-needle arrays; the cleaning operation only requires axial push and pull, without the need for professional tools and skills, reducing labor intensity.

[0021] Maintaining spinning stability: Precisely matched gaps and surface quality ensure no leakage of spinning solution, the damping effect of the elastic sleeve suppresses vibration, and the tip protrusion distance optimizes the electric field distribution, ensuring uniform fiber diameter and consistent quality.

[0022] Wide applicability: By adjusting the size parameters and materials, it can be used for electrospinning of spinning solutions with different viscosities and corrosiveness, including solution spinning and melt spinning, and is suitable for single-needle laboratory equipment and multi-needle industrial production lines. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this utility model.

[0024] Figure 2 This is a schematic diagram of the actual use of this utility model.

[0025] Reference numerals: 1. Needle base; 2. Inner needle; 3. Outer capillary; 4. Connecting and limiting mechanism. Detailed Implementation

[0026] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model.

[0027] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance, quantity, or position.

[0028] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0029] An electrospinning needle, such as Figure 1 As shown, the device includes a needle holder 1, an inner needle 2, an outer capillary tube 3, and a connecting and limiting mechanism 4. The needle holder 1 is made of 304 stainless steel and is cylindrical. One end has an external thread for connecting to the liquid supply line, and the other end has an internal hole for fixing the inner needle 2. The inner needle 2 is also made of 304 stainless steel and is fixed to the needle holder 1 by interference fit or laser welding. The inner needle 2 has an axially penetrating spinning liquid channel with a channel diameter of 0.3 mm. The outer diameter of the inner needle 2 is 1.0 mm, and its length is 25 mm. The outer wall of its end is machined with a precision cylindrical surface with a surface roughness Ra=0.4 μm.

[0030] The outer capillary tube 3 is made of 316L stainless steel, which has excellent resistance to pitting and crevice corrosion. The outer capillary tube 3 has an inner diameter of 1.05 mm, an outer diameter of 1.4 mm, a length of 15 mm, a wall thickness of 0.175 mm, and an inner wall surface roughness Ra = 0.2 μm. The outer capillary tube 3 is slidably sleeved on the outer side of the end of the inner needle 2, with a fitting clearance of 0.025 mm, ensuring both no leakage of the spinning solution under a supply pressure of 0.3 MPa and smooth axial sliding.

[0031] The connecting and limiting mechanism 4 uses a silicone sleeve with a wall thickness of 1.0 mm and a length of 10 mm. Both ends of the sleeve are respectively fitted onto the outer walls of the inner needle 2 and the outer capillary 3. Correspondingly, there are annular grooves with a depth of 0.3 mm and a width of 1.2 mm. The sleeve embeds itself into the grooves to form a reliable axial limit. The elastic restoring force of the sleeve keeps the outer capillary 3 in its initial working position. At this time, the tip of the outer capillary 3 extends 4 mm beyond the tip of the inner needle 2, forming a stable spinning zone.

[0032] The outer capillary tube 3 has an axial anti-slip texture on its outer wall to facilitate the application of force during operation. The inner needle 2 has a guide cone with a cone angle of 20° at its end, and the inlet end of the outer capillary tube 3 has a corresponding guide chamfer to facilitate quick positioning during assembly.

[0033] The working and cleaning process of electrospinning needles is as follows.

[0034] Spinning process: The spinning solution is injected from the supply port, flows through the channels of needle seat 1 and inner needle 2, and flows out from the end of inner needle 2, filling the annular area between the end of inner needle 2 and the tip of outer capillary 3. Under the action of the high voltage electric field applied between the needle and the receiving device, a Taylor cone is formed and stretched into a nanofiber jet.

[0035] Cleaning process: such as Figure 2 As shown, when cleaning is required, turn off the high-voltage power supply. The operator pinches the outer wall of the outer capillary 3 with their fingers and gently pushes it axially towards the needle seat 1. The silicone sleeve is compressed and deformed, allowing the outer capillary 3 to slide backward a distance S (approximately 3-5 mm). During this process, the end and outer wall of the inner needle 2 act like a scraper, removing gel or solid deposits adhering to the inner wall and inner edge of the tip of the outer capillary 3. The scraped material may be pushed into the flow channel between the inner needle 2 and the needle seat 1, and can be flushed away in subsequent cleaning cycles or periodically collected and cleaned. After releasing the hand, the elastic restoring force of the silicone sleeve pushes the outer capillary 3 back to its initial position. Figure 1 (Status), the needle is restored to standby status.

[0036] Although embodiments of the present invention have been shown and described above, it is understood that these embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and alterations to the above embodiments within the scope of the present invention without departing from its principles and spirit. The scope of protection of the present invention is defined by the claims and their equivalents.

Claims

1. An electrospinning needle, characterized in that, include: Needle holder, connected to the spinning solution supply system; The inner needle is fixedly mounted on the needle seat and has a spinning liquid flow channel that extends along the axial direction. The outer capillary is slidably sleeved on the outer side of the end of the inner needle. The inner wall of the outer capillary and the outer wall of the inner needle form a sliding tight fit, and the two can move relative to each other along the axial direction. A connecting limiting mechanism is disposed between the inner needle and the outer capillary to keep the outer capillary and the inner needle coaxially connected. The tip of the outer capillary extends beyond the tip of the inner needle, forming an annular gap for spinning.

2. The electrospinning needle according to claim 1, characterized in that, The connecting and limiting mechanism is an elastic sleeve, with its two ends respectively fitted onto the outer walls of the inner needle and the outer capillary.

3. The electrospinning needle according to claim 2, characterized in that, The sleeve is made of rubber or silicone.

4. The electrospinning needle according to claim 1, characterized in that, The connection limiting mechanism is connected to the inner needle and the outer capillary by a socket connection. The outer walls of the inner needle and the outer capillary are provided with annular grooves, and the two ends of the connection limiting mechanism are embedded in the annular grooves to form axial limiting.

5. The electrospinning needle according to claim 1, characterized in that, The surface roughness Ra of the inner wall of the outer capillary is ≤0.4μm, the surface roughness Ra of the outer wall of the inner needle is ≤0.8μm, and the gap between the two is 0.01-0.05mm.

6. The electrospinning needle according to claim 1, characterized in that, The inner needle has a length of 13-50 mm and an outer diameter of 0.5-2 mm; the outer capillary has a length of 13-16 mm, an inner diameter of 0.6-2.1 mm, and a wall thickness of 0.1-0.3 mm.

7. The electrospinning needle according to claim 1, characterized in that, The distance between the tip of the outer capillary and the tip of the inner needle is 3-5 mm.

8. The electrospinning needle according to claim 1, characterized in that, The outer wall of the inner needle tip is provided with a guide cone surface, and the inlet end of the outer capillary tube is provided with a corresponding guide chamfer. The cone angle of the guide cone surface is 15°-30°.

9. The electrospinning needle according to any one of claims 1-8, characterized in that, The outer wall of the outer capillary is provided with anti-slip texture or operating flange. The anti-slip texture is knurled, mesh-like, or axial ribs, and the operating flange is an annular boss or symmetrically arranged lugs.

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